The present invention generally relates to a photoreceptor (photosensitive) drum and more particularly, to a photoreceptor cartridge unit in which the photoreceptor drum and its peripheral components are integrally accommodated.
In response to recent trends toward compactness for an image forming apparatus such as a copying apparatus, a cartridge unit in which a photoreceptor drum and its peripheral components are integrally accommodated is put to practical use from a maintenance-free viewpoint so that replacement of the components, such as the photoreceptor drum, can be performed by users without the need for calling servicemen. If the photoreceptor drum and one of the components to be replaced after a predetermined time period of operation, for example, a cleaning unit including a container for storing waste toner, are integrally accommodated in the cartridge unit, users can advantageously continue to use the copying apparatus by replacing for themselves the cartridge unit with a new unit without calling a serviceman when need of replacement of the component arises.
However, known cartridge units have such a drawback that since bearing portions of rotary members, such as the photoreceptor drum, are preliminarily attached to a cartridge frame in order to mount the rotary members on the cartridge frame and machine screws or nuts are used for mounting the peripheral components such as the above described cleaner unit on the cartridge frame, the working efficiency will be quite low and the cartridge unit becomes complicated in structure.
Furthermore, in the case where the photoreceptor drum and a corona charger constituted by a discharge wire and a casing are integrally accommodated in the known cartridge unit, machine screws for attaching the corona charger to the cartridge frame are required to be spaced away from the support portions for supporting the discharge wire such that electrical discharge leading from the support portions to the machine screws is prevented, thereby resulting in the difficulty of making the cartridge unit compact in size.